冷卻塔全接觸

McQuayBy

Nick

Chan(陳萬里)中國Cooling

TowerTrainingPrepared

By：Nick

Chan

（陳萬里）By

Nick

Chan(陳萬里)

Cooling

tower

冷卻塔AgendaTraining

Agenda:

Cooling

TowersIntroduction

簡介Types

of

cooling

towers

類型

Assessment

ofcoolingtowers評估

Energy

efficiency

opportunities

節(jié)能方案Introduction

冷卻塔簡介Main

Features

of

Cooling

Towers整體結(jié)構(gòu)IntroductionComponents

of

a

cooling

tower冷卻塔組成部分Frame

and

casing:supportexteriorenclosures

支架和塔體:外部支撐Fill:

facilitate

heat

transfer

by

maximizingwater

/

aircontact填料：為水和空氣提供盡可能大的換熱面積IntroductionSplash

fill

–

droplets

of

water

splash

over,

preventfouling噴淋式—將水呈水霧狀噴出，這樣的方式可以避免塔內(nèi)結(jié)垢。Film

fill

–

layers

of

water

fall

over

(more

efficient),

butmore

expensive水膜式—水呈膜狀順填料表面流下，效率較高但是成本高昂。Cold

water

basin:

receives

water

at

bottomof

tower冷卻水槽：位于冷卻塔底部，接收冷卻水MS1幻燈片6MS1需要定期放水，防止水槽內(nèi)部運(yùn)行時間太長，內(nèi)部產(chǎn)生雜質(zhì)和菌類MC

SYSTEM,

2009/4/22Introduction噴淋式水膜式Introductioncapture

droplets

in

air

stream回收空氣流帶走的水滴Air

inlet

進(jìn)風(fēng)口：entrypoint

of

air

冷卻塔空氣入口Louvers冷卻塔百葉窗：equalize

air

flow

into

the

fill

and

retain

water

within

tower平均進(jìn)氣氣流；保留塔內(nèi)水分Components

of

a

cooling

tower冷卻塔組件Drift

eliminators

收水器:IntroductionNozzles

淋水裝置：spray

water

to

wet

the

fill將冷卻水噴出Fans

風(fēng)機(jī)：deliver

air

flow

in

the

tower向冷卻塔內(nèi)送風(fēng)Propeller

fans

used

in

induced

draft

towers軸流風(fēng)扇用于誘導(dǎo)通風(fēng)冷卻塔Propeller

&

centrifugal

fans

used

in

forced

draft

towers軸流/離心風(fēng)扇用于強(qiáng)制通風(fēng)冷卻塔Training

Agenda:

Cooling

TowersIntroduction

簡介Types

of

cooling

towers

類型

Assessment

ofcoolingtowers評估

Energy

efficiency

opportunities

節(jié)能方案Types

of

Cooling

Towers

冷卻塔種類Natural

Draft

Cooling

Towers自然通風(fēng)冷卻塔Hot

air

moves

through

tower密度較小的熱空氣自冷卻塔頂部流出Fresh

coolairisdrawnintothetowerfrombottom密度較大的冷空氣自塔底部進(jìn)入冷卻塔填補(bǔ)Types

of

Cooling

Towers

冷卻塔種類Natural

Draft

Cooling

Towers

自然冷卻塔No

fan

required不需風(fēng)機(jī)Concrete

tower

<200m混凝土塔<200

mUsed

for

large

heat

duties用于大熱量的冷卻Types

of

Cooling

Towers

冷卻塔種類Natural

Draft

Cooling

Towers

自然冷卻塔橫流對流Types

of

Cooling

Towers

冷卻塔類型兩種冷卻塔橫流對流Large

fanstoforceair

throughcirculatedwater大功率風(fēng)機(jī)強(qiáng)制空氣與循環(huán)水的換熱Water

falls

over

fill

surfaces:

maximum

heattransfer填料表面的水膜可以最大限度地與空氣進(jìn)行換熱Types

of

Cooling

Towers

冷卻塔種類Mechanical

Draft

Cooling

Towers機(jī)械通風(fēng)冷卻塔Types

of

Cooling

Towers

冷卻塔種類Cooling

rates

depend

on

many

parameters冷卻效率的決定因素有很多Large

range

ofcapacities多種冷卻能力備選Canbe

grouped,

e.g.

8-cell

tower可以多冷卻塔同時工作，例如8塔聯(lián)控。MS2幻燈片16MS2濕球溫度，填料，風(fēng)扇MC

SYSTEM,

2009/4/22Forced

draft強(qiáng)制通風(fēng)冷卻塔Induced

draft

cross

flow誘導(dǎo)通風(fēng)橫流冷卻塔Induced

draft

counterflow誘導(dǎo)通風(fēng)逆流冷卻塔Types

of

Cooling

Towers

冷卻塔種類

Mechanical

Draft

Cooling

TowersThree

types

機(jī)械通風(fēng)冷卻塔分為三類：Types

of

Cooling

TowersForced

Draft

Cooling

TowersAir

blown

through

tower

bycentrifugal

fan

at

air

inlet空氣由離心風(fēng)扇吹入通風(fēng)口Advantages:

suited

for

highair

resistance

&

fans

arerelatively

quiet優(yōu)勢：適用于氣流阻力較大的塔體；離心風(fēng)扇噪聲相對較小Disadvantages:

recirculation

due

to

high

air-entry

and

lowair-exit

velocities劣勢：由于進(jìn)氣流速高于排氣流速，會出現(xiàn)回流。19Cooling

Tower

BasicsForced Draft

強(qiáng)制通風(fēng)Counter

flow

Tower

逆流冷卻塔Water

is

sprayed

on

to

the

fill

andfalls

to

the

tower

basin.冷卻水被噴淋在填料上，向下流入冷卻水槽Air

is

blown

up

through

the

fill

andevaporates

some

of

the

water

andreduces

the

water

temperature.空氣從底部強(qiáng)制吹入，在填料內(nèi)與水接觸蒸發(fā)部分冷卻水，從而降低水溫Types

of

Cooling

TowersInduced

Draft

Cooling

Towers誘導(dǎo)通風(fēng)冷卻塔Two

types誘導(dǎo)通風(fēng)冷卻塔分兩類：Cross

flow

橫流式誘導(dǎo)通風(fēng)冷卻塔Counter

flow

逆流式誘導(dǎo)通風(fēng)冷卻塔Types

of

Cooling

TowersAdvantage:

less

recirculation

than

forceddraft

towers

&

lower

motor

running

cost優(yōu)勢：回流程度低于強(qiáng)制通風(fēng)冷卻塔；風(fēng)機(jī)運(yùn) 行費(fèi)用小于強(qiáng)制通風(fēng)冷卻塔。Disadvantage:

fans

and

motor

drivemechanism

require

weather-proofing劣勢：風(fēng)扇與電機(jī)的機(jī)械傳動需要防水設(shè)計(jì)Hot

water

enters

at

the

top

熱水從頂部進(jìn)入冷卻塔Air

enters

at

bottom

and

exits

at

top空氣通過風(fēng)扇強(qiáng)制誘導(dǎo)，從底部進(jìn)入冷卻塔Uses

induced

draft

fans

使用強(qiáng)制誘導(dǎo)風(fēng)扇Types

of

Cooling

TowersInduced

Draft

Counter

Flow

CT23Cooling

Tower

BasicsInduced

Draft

誘導(dǎo)通風(fēng)Counter

flow

Tower

逆流式Water

is

sprayed

on

to

theFill

and

falls

to

the

towerBasin冷卻水從頂部噴入，流經(jīng)填料層進(jìn)入冷卻水槽Air

is

drawn

through

theFill

and

evaporates

someOf

the

water

and

reducesThe

remaining

watertemperature.空氣由誘導(dǎo)風(fēng)機(jī)引入冷卻塔從底部，在填料內(nèi)與水接觸蒸發(fā)部分冷卻水，從而降低水溫Due

to

their

pressurized

spray

water

distributionsystem

因?yàn)榇祟惱鋮s塔內(nèi)的加壓配水噴淋裝置：Advantages

優(yōu)勢: Increased

tower

height

accommodates

longer

ranges

and

closerapproaches通過增加塔的高度來獲得更長的換熱流程與更小的冷幅More

efficient

use

of

air

due

to

finer

droplet

size

from

pressuresprays由于加壓噴淋裝置可以噴出更小的水滴，因此換熱效率較高Cooling

Tower

BasicsInduced

draft

–

counter

flow逆流式誘導(dǎo)通風(fēng)冷卻塔Cooling

Tower

BasicsDisadvantages

劣勢：Increased

system

pumping

head

requirements系統(tǒng)水泵壓頭增加Increased

energy

consumption

and

operating

costs能量需求增大，運(yùn)行費(fèi)用增加Distribution

nozzles

difficult

to

inspect

and

clean冷卻水噴頭不易維護(hù)和清潔Requires

extra

distributor

and

external

piping

costs需要配水系統(tǒng)以及相關(guān)管路，因此初投資增加Water

enters

top

and

passes

over

fill

冷卻水從頂部進(jìn)入，流經(jīng)填料層Air

enters

on

one

side

or

opposite

sides

空氣從一側(cè)或兩側(cè)進(jìn)入Induced

draft

fan

draws

air

across

fill

誘導(dǎo)風(fēng)機(jī)使空氣橫向流過填料層Types

of

Cooling

TowersInduced

Draft

Cross

Flow

CT橫流式誘導(dǎo)通風(fēng)冷卻塔27Cooling

Tower

BasicsInduced

DraftCross

Flow

TowerWater

is

sprayed

on

to

theFill

and

falls

to

the

towerBasin.

Fill

is

deeper

largerSurface

area.冷卻水噴淋至填料層，從頂部流至底部的冷卻水槽Air

is

drawn

through

theFill

and

evaporates

someOf

the

water

and

reducesThe

watertemperature.Less

airrequired空氣由誘導(dǎo)風(fēng)機(jī)引入冷卻塔側(cè)面，在填料內(nèi)橫向流動與水接觸蒸發(fā)部分冷卻水，從而降低水溫Due

to

their

gravity

flow

hot

water

distribution

system由于此類冷卻塔的水屬于自然流配水系統(tǒng)：Advantages

優(yōu)勢：Low

pumping

head低水泵壓頭Lower

first

cost

pumping

systems較低的水泵初投資Lower

annual

energy

consumption

and

operating

costs較低的年運(yùn)行能耗和費(fèi)用Accepts

larger

variation

in

water

flow

without

adverse

effect

on

the

waterdistribution

pattern流量變化較大時不會對配水系統(tǒng)造成不利的影響Cooling

Tower

BasicsInduced

draft

–

cross

flow橫流式誘導(dǎo)通風(fēng)冷卻塔Cooling

Tower

BasicsDisadvantages

劣勢：Low

pressure

head

on

the

distribution

pan

may

encourage

orificeclogging

and

less

water

breakup

at

spray

nozzle低壓頭會導(dǎo)致噴頭易于堵塞以及冷卻水噴出時不能很好的分散成細(xì)密水霧Exposure

to

air

in

the

hot

water

basin

may

accelerate

algae

growth熱水水槽直接暴露于空氣中會導(dǎo)致藻類的滋生Larger

footprint占地面積較大Training

Agenda:

Cooling

TowersIntroduction

簡介Types

of

cooling

towers

類型

Assessment

ofcoolingtowers評估

Energy

efficiency

opportunities

節(jié)能方案Assessment

of

Cooling

TowersMeasured

Parameters

應(yīng)測量的參數(shù)Wet

bulb

temperature

of

air

空氣濕球溫度Dry

bulb

temperature

of

air

空氣干球溫度Cooling

tower

inlet

water

temperature

冷卻塔進(jìn)水溫度Cooling

tower

outlet

water

temperature

冷卻塔出水溫度Electrical

readings

of

pump

and

fan

motors水泵和電機(jī)運(yùn)行參數(shù)Water

flow

rate

水流速度Air

flow

rate

空氣流速運(yùn)行參數(shù)Range

冷卻水溫差A(yù)pproach

冷幅Effectiveness

效率Cooling

capacity

冷卻塔容量Evaporation

loss

蒸發(fā)損失Cycles

of

concentration

濃縮倍數(shù)Blow

down

losses

排污損失Liquid/Gas

ratio

液體/氣體比Assessment

of

Cooling

TowersPerformance

Parameters1.Range

冷卻水溫差Difference

betweencooling

water

inlet

andoutlet

temperature:冷卻水進(jìn)出水溫差：Range

(°C)

=

CW

inlettemp

–

CW

outlet

tempHigh

range

=

goodperformance大溫差=高性能冷卻水溫差冷幅冷卻水溫度(進(jìn)水)冷卻水溫度(出水)濕球溫度(進(jìn)水)進(jìn)冷卻塔(出水)出冷卻塔Assessment

of

Cooling

Towers2.Approach

冷幅Difference

between

coolingtower

outlet

cold

watertemperature

and

ambientwet

bulb

temperature:冷卻塔出水溫度與入口空氣濕球溫度的差值：Approach

(°C)

=CW

outlet

temp

–

Wet

bulbtempLow

approach

=

goodperformance小冷幅=高性能冷卻水溫差冷幅Hot

Water

Temperature

(In)Cold

Water

Temperature

(Out)Wet

Bulb

Temperature

(Ambient)(In)

to

the

Tower(Out)

from

theTowerAssessment

of

Cooling

Towers3.Effectiveness

效率Effectiveness

in

%=

Range

/

(Range

+

Approach)效率=冷卻水溫差/（冷卻水溫差+冷幅）High

effectiveness

=

goodperformance高效率=高性能Assessment

of

Cooling

Towers冷卻水溫差冷幅冷卻水溫度(進(jìn)水)冷卻水溫度(出水)濕球溫度(進(jìn)水)進(jìn)冷卻塔(出水)出冷卻塔4.Cooling

Capacity

冷卻塔容量Heat

rejected

in

kCal/hr

or

tonsof

refrigeration

(TR)=

mass

flow

rate

of

water

Xspecific

heat

X

temperaturedifference冷卻塔容量單位為“千卡每小時”或者“冷噸”冷卻塔容量=冷卻水質(zhì)量流量X水的比熱容X溫差High

cooling

capacity

=

goodperformance大容量=高性能Assessment

of

Cooling

Towers冷卻水溫差冷幅冷卻水溫度(進(jìn)水)冷卻水溫度(出水)濕球溫度(進(jìn)水)進(jìn)冷卻塔(出水)出冷卻塔5.Evaporation

Loss

蒸發(fā)損失Water

quantity

(m3/hr)evaporated

for

cooling

duty蒸發(fā)損失的單位為(m3/hr)，表示每小時因?yàn)槔鋮s而損失的水量=

theoretically,

1.8

m3

for

every10,000,000

kCal

heat

rejected理論上蒸發(fā)損失為1.8立方米/1千萬千卡=0.00085x1.8x流量(m3/hr)x冷卻水溫差A(yù)ssessment

of

Cooling

Towers冷卻水溫差冷幅冷卻水溫度(進(jìn)水)冷卻水溫度(出水)濕球溫度(進(jìn)水)進(jìn)冷卻塔(出水)出冷卻塔Assessment

of

Cooling

TowersEvaporation

Loss

蒸發(fā)損失CoolingTowerIndustry(CTI)RatesTowers

At

ARICondenserWater

工業(yè)冷卻塔的ARI工況：Water

flow

rate

across

cooling

tower

=

0.054

(L/s)

/

Kw冷卻塔流量=0.054

(L/s)/KwCooling

tower

capacity=3500kW

冷卻塔容量=3500kW29.4℃Leaving

Fluid

出水溫度29.4

℃35℃Entering

Fluid

進(jìn)水溫度35

℃Use

the

formula

from

previous

page

應(yīng)用前一頁的公式:=0.00085

x

1.8

x

流量(m3/hr)x

冷卻水溫差=

0.00085

x

1.8

x

680.4

x

(35

–

29.4)=

5.82

m3/hrA

3500

kW

Tower

Can

Consume

5820

Liters

Per

Hour

of

Make

up

Water

Due

ToEvaporation

一個3500kW冷卻塔的冷卻水蒸發(fā)量為5820升每小時Assessment

of

Cooling

TowersCycles

of

concentration

濃縮倍數(shù)Ratio

of

dissolved

solids

in

circulating

water

to

the

dissolvedsolids

inmake

upwater

循環(huán)水中固態(tài)溶解物含量與補(bǔ)充水中固態(tài)溶解物的含量之比Increase

this

to

reduce

water

loss增加此比例可減小蒸發(fā)損失Blow-down排污量Depend

on

cycles

of

concentration

and

the

evaporation

losses決定于循環(huán)水濃度與蒸發(fā)損失Blow-down

=

circulating

water

removed

amount

to

maintain

theamount

of

dissolved

solids

and

other

impurities

at

an

acceptablelevel

=

Evaporation

Loss

/

(C.O.C.

–

1)排污量=為將固態(tài)溶解物和其他雜質(zhì)濃度維持在可接受范圍內(nèi)而排出的循環(huán)水量=蒸發(fā)損失/（

C.O.C.–1）8.Liquid

Gas

(L/G)Ratio

液氣比Ratio

between

water

and

air

mass

flow

rates水與空氣的質(zhì)量流量之比Heat

removed

from

the

water

must

be

equal

to

theheat

absorbed

by

the

surrounding

air冷卻水散發(fā)的熱量等于空氣吸收的熱量L(T1

–

T2)

=

G(h2

–

h1)L/G

=

(h2

–

h1)

/

(T1

–

T2)T1=hot

water

temp

(oC)熱水溫度（冷卻塔進(jìn)水）T2=cold

water

temp

(oC)冷水溫度（冷卻塔出水）Enthalpy

of

air

water

vapor

mixture

at

inlet

wet

bulb

temp

(h1)andoutlet

wet

bulb

temp

(h2)冷卻塔進(jìn)口（空氣與水蒸氣混合）溫度對應(yīng)的焓值(h1)與出口溫度（濕球溫度）的焓值(h2)Assessment

of

Cooling

Towers41Cooling

Tower

Process

冷卻塔工作流程354555758595115103.9kJ/kg78.5kJ/kg6580%60%40%20%10%30%Air

Enters

at35

℃

DB26

℃

WB空氣35℃DB

26℃WBAir

Leaves

Saturatedat30.8

℃2.

30.8℃飽和空氣離開冷卻塔3.

Entering

Air

Enthalpyis

78.5

kJ/kg3.

進(jìn)口空氣的焓值是78.5kJ/kg4.

Leaving

AirEnthalpyis

103.9

kJ/kg出口空氣的焓值是103.9kJ/kg5.Water

VaporizedLatent

Heat

is

2430

kJ/kg11

g

water

absorbs

26.7kJ

heat

duringevaporating5.

蒸汽的潛伏熱值是2430kJ/kg，11g的水吸取

26.7kJ的熱量6.

Air

Sensible

heatis26.7

–

25.4

=

1.3

kJ6.

空氣的感熱為26.7

–

25.4

=

1.3

kJ17.3g105

28.3gL/G

=

(h2

–

h1)

/(T1

–

T2)L/G

=

(103.9

–

78.5)

/

(35

–30.8)L/G

=

25.4

/

11

=6.05(g/g)Training

Agenda:

Cooling

TowersIntroduction

簡介Types

of

cooling

towers

類型Assessment

of

coolingtowers

評估Energy

efficiency

opportunities

節(jié)能方案Energy

Efficiency

OpportunitiesSelecting

a

cooling

tower選擇冷卻塔Fills填料Pumps

and

water

distribution水泵與配水設(shè)備Fans

andmotors風(fēng)扇與電機(jī)Energy

Efficiency

OpportunitiesSelecting

a

cooling

tower

選擇冷卻塔Capacity

冷卻塔容量Heatdissipation

(kCal/hour)散熱量(kCal/hour)Circulatedflowrate(m3/hr)循環(huán)水流量(m3/hr)Other

factors其它因素Energy

Efficiency

OpportunitiesSelecting

a

cooling

towerRange

冷卻水溫差Range

determined

by

process,

not

by

system冷卻水溫差取決于換熱過程而不是設(shè)備Approach

冷幅Closer

to

the

wet

bulb

temperature?

=

Bigger

size

cooling

tower?

=

More

expensive越接近濕球溫度=更大的冷卻塔=更多的投資Energy

Efficiency

Opportunitiesby

the

desiredDetermined

by

process決定于換熱過程Required

cooling

is

controlledoperating

temperature合適的工況下才能保證需要的冷量High

heat

load

=

large

size

and

cost

of

coolingtower熱負(fù)荷大=更大的冷卻塔與更多的設(shè)備費(fèi)用1.

Selecting

a

cooling

towerHeat

Load熱負(fù)荷Energy

Efficiency

OpportunitiesWet

bulb

temperature

–

considerations:關(guān)于濕球溫度Water

is

cooled

to

temp

higher

than

wet

bulb

temp冷卻水出水溫度高于空氣濕球溫度Conditions

at

tower

site冷卻塔坐落位置的具體情況Not

to

exceed

5%

of

design

wet

bulb

temp濕球溫度不可高于設(shè)計(jì)濕球溫度的5%及以上The

designed

wet

bulb

temp

is

refer

to

ambient

WB

(preferred)orinlet

此濕球溫度指的是環(huán)境濕球溫度（推薦）或者空氣入口處濕球溫度Can

tower

deal

with

increased

wet

bulb

temp?冷卻塔能否適應(yīng)較高的濕球溫度Relationship

range,

flow

and

heat

load溫差，流量與熱負(fù)荷的關(guān)系Range

increases

with

increased：以下兩項(xiàng)增加的情況下溫差會增大：Amount

circulated

water

(flow)

循環(huán)水量（流量）Heatload

熱負(fù)荷Causes

of

range

increase

溫差增大的原因如下：Inlet

water

temperature

increases

進(jìn)水溫度升高Exit

water

temperature

decreases

出水溫度降低Consequence

=

larger

tower冷卻水溫差增大=更大的冷卻塔Wet

bulb

temperature

influence

on

chillerperformance

濕球溫度對機(jī)組運(yùn)行的影響Lowering

condenser

water

impact

onchiller

improvement冷卻水溫下降對機(jī)組性能的影響0.56

Deg

CLowering

condenser

water

impact

oncooling

tower冷卻水溫下降對機(jī)組性能的影響3.9

Deg

CGet

temperature

data

from

customer用戶提供的濕球溫度變化圖1月1日1月15日1月29日2月12日2月26日3月12日3月26日4月9日4月23日5月7日5月21日6月4日6月18日7月2日7月16日7月30日8月13日8月27日9月10日9月24日10月8日10月22日11月5日11月19日12月3日12月17日12月31日濕球溫度(℃)濕球溫度變化圖35302520151050-5-10濕球溫度WB

≤

26Deg

C=337

DaysWB

＞

26

DegC

=27

DaysEnergy

Efficiency

OpportunitiesFill

media

填料Hot

water

distributed

over

fill

mediaandcools

down

through

evaporation熱水經(jīng)過配水設(shè)備流經(jīng)填料介質(zhì)，蒸發(fā)降溫Fill

media

impacts

electricity

use填料介質(zhì)影響冷卻塔用電量Efficiently

designed

fill

media

reduces

pumping costs

高效填料介質(zhì)可以節(jié)約管路投資Fill

media

influences

heat

exchange:

surface

area, duration

of

contact,turbulence填料介質(zhì)影響換熱效率：表面積，接觸時間與湍流Energy

Efficiency

Opportunities噴淋式水膜式低堵塞水膜式L/G1.1

–

1.51.5

–

2.01.4

–

1.8有效換熱面積30

–

45

m2/m3150

m2/m385

-

100

m2/m3填料高度5

–

10

m1.2

–

1.5

m1.5

–

1.8

m壓頭9

–

12

m5

–

8

m6

–

9

m風(fēng)量需求高很低低2.Fill

media

填料介質(zhì)Comparing

3

fill

media:

film

fill

m